This invention relates to a plumbing fixture, e.g., a bathtub, shower receptor, lavatory, kitchen sink, etc., of laminar construction fabricated from a multilayer polymeric composite in which a relatively thin polymeric cosmetic, or finish, layer is chemically bonded to a relatively thick, reinforced, cross-linked, isocyanate-modified dense thermosetting unsaturated polyester or polyether resin foam layer to provide a delamination-resistant structure.
U.S. Pat. No. 4,664,982 describes a composite structure, e.g., a reinforced enameled steel product, having high impact strength and thermal shock resistance. The composite structure is formed having bonded thereto a finish layer on one side thereof and on the other side a layer of reinforced plastic to provide a laminate. While the composite structure and the plumbing fixtures disclosed to be manufactured from it possess generally excellent physical and mechanical properties as a result of the chemical bonding, or union, of the reinforced plastic layer to the enameled steel layer. However, due to the presence of steel, the structure is fairly heavy for a given level of strength and stiffness.
U.S. Pat. No. 4,053,545 describes a laminated structural foam possessing an injection molded thermoplastic fiber-reinforced dense foam backing, e.g., one of polyethylene or polystyrene, adhesively bonded to a thermoformed finish layer, e.g., one of acrylic such as Swedcast cast acrylic sheet type 300. The laminated foam is said to be useful in the manufacture of wash basins, shower stalls, bathtub, etc. No mention or suggestion is made in this patent of chemical bonding a thermosetting foam backing layer to a thermoplastic finish layer.
U.K. Patent Specification No. 904,763 describes a bathtub possessing a basic shell formed of thermoplastic material, e.g., a polymethacrylic acid ester, and a foamed synthetic resin material basic body. A foamed synthetic resin, e.g., a polyurethane foam, interposed between the shell and basic body may be bonded thereto. Solvent or chemical bonding of adjacent lamina is neither disclosed nor suggested.
U.K. Patent Applications GB No. 2 040 676A and GB No. 2 148 786A both disclose a laminar bathtub construction in which a thermoformed acrylic surface layer is backed with a fiber-reinforced rigid backing layer. Neither disclosure suggests a chemical bonding procedure. Delamination of the finish layer from the backing layer is a problem with bathtubs and other plumbing features constructed with laminates of the type illustrated in these disclosures.
It is an object of the present invention to provide a plumbing fixture, e.g., a bathtub, shower receptor, lavatory, kitchen sink, etc., constructed from a multilayer polymeric composite which is significantly lighter than a metal-containing, e.g., steel-containing, polymeric composite for an approximately equivalent level of strength and stiffness.
It is another object of the present invention to provide a plumbing fixture molded from a multilayer polymer composite which is exceptionally resistant to delamination due to the chemical bonding of dissimilar polymer layers.
It is yet another object of the present invention to provide a plumbing fixture of composite construction which lends itself to manufacture in whole or in part by RIM or RRIM technology.